Fractional calculus for scientists and engineers MD Ortigueira Springer Science & Business Media, 2011 | 878 | 2011 |

What is a fractional derivative? MD Ortigueira, JAT Machado Journal of computational Physics 293, 4-13, 2015 | 463 | 2015 |

On the HHT, its problems, and some solutions RT Rato, MD Ortigueira, AG Batista Mechanical systems and signal processing 22 (6), 1374-1394, 2008 | 390 | 2008 |

Riesz potential operators and inverses via fractional centred derivatives MD Ortigueira International Journal of Mathematics and Mathematical Sciences 2006, 2006 | 314 | 2006 |

On the fractional signals and systems R Magin, MD Ortigueira, I Podlubny, J Trujillo Signal Processing 91 (3), 350-371, 2011 | 282 | 2011 |

An introduction to the fractional continuous-time linear systems: the 21st century systems MD Ortigueira IEEE Circuits and Systems Magazine 8 (3), 19-26, 2008 | 239 | 2008 |

Fractional signal processing and applications MD Ortigueira, JAT Machado Signal processing 83 (11), 2285-2286, 2003 | 220* | 2003 |

Fractional model of an electrochemical capacitor V Martynyuk, M Ortigueira Signal Processing 107, 355-360, 2015 | 131 | 2015 |

Fractional calculus applications in signals and systems MD Ortigueira, JAT Machado Signal Processing 86 (10), 2503-2504, 2006 | 126 | 2006 |

Introduction to fractional linear systems. Part 1: Continuous-time case MD Ortigueira IEE Proceedings-Vision, Image and Signal Processing 147 (1), 62-70, 2000 | 111 | 2000 |

A coherent approach to non-integer order derivatives MD Ortigueira Signal Processing 86 (10), 2505-2515, 2006 | 108 | 2006 |

Fractional central differences and derivatives MD Ortigueira IFAC Proceedings Volumes 39 (11), 58-63, 2006 | 108 | 2006 |

Introduction to fractional linear systems. Part 2: discrete-time case MD Ortigueira IEE Proceedings-Vision, Image and Signal Processing 147 (1), 71-78, 2000 | 107 | 2000 |

A critical analysis of the Caputo–Fabrizio operator MD Ortigueira, JT Machado Communications in Nonlinear Science and Numerical Simulation 59, 608-611, 2018 | 97 | 2018 |

On the initial conditions in continuous-time fractional linear systems MD Ortigueira Signal Processing 83 (11), 2301-2309, 2003 | 92 | 2003 |

Identifying a transfer function from a frequency response D Valério, MD Ortigueira, J Sá da Costa Journal of computational and nonlinear dynamics 3 (2), 021207, 2008 | 85 | 2008 |

Variable order fractional systems MD Ortigueira, D Valério, JT Machado Communications in Nonlinear Science and Numerical Simulation 71, 231-243, 2019 | 77 | 2019 |

Which derivative? M Ortigueira, J Machado Fractal and Fractional 1 (1), 3, 2017 | 71 | 2017 |

From differences to derivatives MD Ortigueira, F Coito Fractional Calculus and Applied Analysis 7 (4), 459, 2004 | 69 | 2004 |

Discrete-time differential systems MD Ortigueira, FJV Coito, JJ Trujillo Signal Processing 107, 198-217, 2015 | 68 | 2015 |